The Role of RNA in Tau Aggregation

项目摘要：神经退行性疾病是一组神经退行性疾病，其特征是 在尸检病人大脑中发现的微管相关蛋白Tau(Tau)。这些障碍包括 阿尔茨海默病(AD)、慢性创伤性脑病(CTE)和额颞痴呆(FTD)。广告 仅此一项就是美国第六大死因(影响超过570万人)，目前还没有治愈方法， 预计未来几年患者数量将大幅增加。 Tauopathy可以由tau的突变引起，这种突变促进了tau的聚集(如在FTD中)或由 触发tau聚集的细胞外应激源(如AD和CTE)。细胞外应激源如何导致 细胞内tau的聚集是未知的。最近的一些观察表明，应激颗粒 (SGS)，一种对细胞应激反应形成的细胞质RNA和蛋白质组装，可能参与其中 在tau聚集体的形成和持久性方面，操纵SGS可能预示着新的治疗方法 战略。我提出了一个模型，在这个模型中，细胞应激源(如神经炎症、病毒感染、淀粉样蛋白B) 推动形成招录tau的SGS。SGS会在局部产生较高浓度的tau和rna，使其成核。 并稳定tau聚集体并增加其毒性。该模型得到了体外和体内实验的支持。 证据表明，RNA促进了tau聚集，在AD患者中，RNA被隔离成tau聚集体 减少SG的形成降低了tau的毒性。 我的初步数据显示，由神经炎性化合物诱导的应激颗粒， 前列腺素J2，与tau共定位。电子显微镜和硫代黄素T荧光也表明 Rna与tau在体外孵育会导致tau聚集体的形成，这些聚集体由成对的螺旋细丝组成。 含有核糖核酸的。最后，我已经通过RNAseq和单分子荧光原位杂交显示了 (SmFISH)体内tau聚集体包含多种RNA(rRNAs、mRNAs、nRNAs和lncRNAs)和 有些RNA比其他的更丰富。 这项提案的目标1将识别和操纵与tau结合的RNA水平 疾病相关模型系统中的非聚集状态和聚集状态。成功完成这一目标将 建议1)哪组RNA作为tau聚集的辅助因子，2)tau聚集体中的RNA是否相似 对于SGS，以及3)特定RNA的隔离是否有助于tau毒性。本提案的目标2将 操作SG形成和RNA稳定性，然后测量这些操作如何影响tau 聚合。这一目标的结果将决定RNA和SGS在肺炎的形成和持续中扮演什么角色 牛磺酸聚合体。总的来说，这项建议旨在测试SGS将细胞外应激和 细胞内tau聚集，希望找到治疗衰弱的新治疗策略 神经退行性疾病，如阿尔茨海默病。

PROJECT SUMMARY: Tauopathies are a group of neurodegenerative diseases characterized by aggregates of the Microtubule Associated Protein Tau (tau) found in the brains of patients on autopsy. These disorders include Alzheimer's disease (AD), chronic traumatic encephalopathy (CTE), and frontotemporal dementia (FTD). AD alone is the 6th leading cause of death in the US (affecting more than 5.7 million), no cure is currently available, and the number of patients is expected to substantially increase in the coming years. Tauopathies can be caused by mutations in tau that promote its aggregation (as in FTD) or by extracellular stressors that trigger tau aggregation (as in AD and CTE). How extracellular stressors lead to intracellular tau aggregation is unknown. A number of recent observations indicate that stress granules (SGs), a type of cytosolic RNA and protein assembly that forms in response to cellular stress, might be involved in the formation and persistence of tau aggregates and manipulating SGs could indicate new therapeutic strategies. I propose a model where cellular stressors (e.g., neuroinflammation, viral infection, amyloid-b) promote the formation of SGs that recruit tau. SGs create high local concentrations of tau and RNA that nucleate and stabilize tau aggregates and contribute to their toxicity. This model is supported by in vitro and in vivo evidence suggesting that RNA promotes tau aggregation, RNA is sequestered into tau aggregates in AD patient brains, and that reducing SG formation decreases tau toxicity. My preliminary data shows that stress granules induced by the neuroinflammatory compound, prostaglandin J2, colocalize with tau. I have also shown by electron microscopy and thioflavin T fluorescence that incubating RNA with tau in vitro causes the formation of tau aggregates made up of paired helical filaments that contain RNA. Finally, I have shown by RNAseq and by single molecule fluorescence in situ hybridization (smFISH) that in vivo tau aggregates contain a diversity of RNAs (rRNAs, mRNAs, snRNAs, and lncRNAs) and some RNAs are more enriched than others. Aim 1 of this proposal will identify and manipulate the levels of RNAs that are bound by tau in unaggregated and aggregated states in disease relevant model systems. Successful completion of this aim will suggest 1) what set of RNAs act as cofactors for tau aggregation, 2) whether the RNAs in tau aggregates are similar to SGs, and 3) whether sequestration of specific RNAs contributes to tau toxicity. Aim 2 of this proposal will manipulate SG formation and RNA stability and then measure how these manipulations influence tau aggregation. Results of this aim will determine what role RNA and SGs play in the formation and persistence of tau aggregates. Broadly, this proposal aims to test the hypothesis that SGs link extracellular stress and intracellular tau aggregation with the hope of identifying new therapeutic strategies to treat debilitating neurodegenerative diseases such as AD.